Electrospraying refers to methods in which a voltage is applied to a liquid (e.g., an ionic liquid or other suitable liquid) to produce ions and/or small droplets of charged liquid. In many electrospraying systems, the liquid is fed to a tip of a protrusion (e.g., a needle). Application of a sufficiently high voltage results in electrostatic repulsion within components of the liquid. The electrostatic repulsion counteracts the surface tension of the liquid, and a stream of liquid erupts from the surface. In many electrospraying systems, when the liquid is fed to the tip of the protrusion and the voltage is applied, varicose waves on the surface of the resulting liquid jet lead to the formation of small and highly charged liquid droplets, which are radially dispersed due to Coulomb repulsion.
While electrospraying is known in the art, most electrospraying systems include a single protrusion, for example, in the form of a single needle. Electrospraying systems that include multiple protrusions are generally not able to discharge liquid from the protrusions in a uniform fashion. Increasing the throughput of such systems while avoiding degradation in performance has proven to be difficult. Increasing the throughput from a single protrusion has resulted in modest improvement, but has generally been accompanied by deterioration of the spread in the properties of the emitted liquid (e.g., size, shape, and the like). Increasing throughput by utilizing large arrays with high protrusion density has proven to be challenging.